Delayed Fluorescence and Amplified Chirality via Modified Substitution Position for Deep-red Circularly Polarized Organic Light Emitting-diodes

Developing easily accessible deep-red/near-infrared circularly polarized emitters for practical organic light-emitting diodes remains a significant challenge. Here, a practical strategy has been proposed for developing deep-red circularly polarized delayed fluorescent emitters based on a novel chiral acceptor platform. By changing triphenylamine (TPA) substitution position from para to meta, R/S-M-TBBTCN demonstrated thermally activated delayed fluorescence (TADF) properties with a delayed lifetime of 6.6 µs that R/S-P-TBBTCN doesn’t have. Furthermore, R/S-M-TBBTCN showed a 65 nm red-shift in emission and a 10-fold enhancement in asymmetry factor (g_lum), compared with R/S-P-TBBTCN. The solution-processed nondoped circularly polarized organic light-emitting diodes (CP-OLEDs) based on R-M-TBBTCN display deep-red emission and 2.2% external quantum efficiency.